Marathon and relay runners make their way along Riverside on the Windsor side of the Detroit Free Press/Talmer Bank Marathon today. / REGINA H. BOONE/Detroit Free Press

A small army descended upon downtown Detroit under the cover of darkness this morning, preparing for another record day for the Detroit Free Press/Talmer Bank Marathon.

This small army consisted of runners, walkers, wheelers and handcyclists — plus volunteers and spectators — for the 35th edition of one of the city’s signature events. To be in the right place at the right time, thousands upon thousands of people needed to be in position long before sunrise at 7:53 a.m.

They arrived under clear skies and crisp conditions but little wind. The temperature stood at 42 degrees at 6 a..m., with the promise of plenty of sunshine and 50 or so degrees by 11 a.m.

Last year, the event — actually a series of distance races — surpassed 20,000 participants for the first time. This year, nearly 24,000 participated, according to race organizers, and the event was declared a sellout in August.

A little perspective: At the turn of the century, the Free Press Marathon drew 3,588 participants. This morning’s field will be nearly 670% higher.

The starting gun sounded at 6:58 a.m. at Fort and Second, outside the Free Press building and the Doubletree Hotel, when the disability division started the horde of runners. At 7 a.m. the first of 11 waves of marathoners, half-marathoners and relay runners headed out spaced two minutes apart. (The waves help ease congestion in the opening miles and in the approach to the Ambassador Bridge, one of the two international border crossings that makes the Detroit marathon unique in distance running.)

After the bridge, the course goes along the Windsor waterfront, back to the U.S. through the Detroit-Windsor Tunnel, around Cobo Center and Joe Louis Arena, through Corktown and eventually east of downtown to Belle Isle and Indian Village before returning west to the starting area on Fort.

Besides the marathon, half and five-person relay, there also is a 5K run/walk and a new race, a half marathon that stays entirely on U.S. soil (it covers, basically, the back half of the marathon course).

Detroit has the only marathon in North America that includes two international border crossings and the only Underwater Mile in distance racing (thanks to the tunnel).

The event has received national recognition in running circles recently.

Marathon & Beyond magazine included Detroit in its ranking of the Top 25 finisher medals for North American marathons. Competitor magazine included Detroit when picking its 26 most memorable miles from marathons across the country. The magazine called the mile over the bridge as “more scenic” but the mile through the tunnel the “more memorable.” Rodale Publishing (parent of Runner’s World magazine) selected Detroit as one of its 10 best events for first-time marathoners.

This year’s field includes runners from all 50 states and 16 countries. About 85% of the runners live in Michigan. The average runner is 38 years old, about the national figure for distance races.

And the field is 57% female. “Detroit runs like a girl,” said Rich Harshbarger, executive race director and vice president of consumer marketing and communications for the Detroit Media Partnership.

Conquered: The Official Marathon Afterparty begins at 9 a.m. on Lafayette between Third and Lodge Service Drive (one block north from finish). It runs until 2 p.m. There is no admission charge, and it is open to all entrants and the general public.

The event will feature music from Larry Lee (a former Lion) and the Back in the Day Band. Plus: local food truck favorites Dago Joe’s, Jacques’ Tacos, People’s Pierogi Collective and Green Zebra; interactive games, face painters, balloon twisters and a photo booth; and official race merchandise tent. Beer sales start at noon.